To clarify the effects of glass composition and heat-treatment conditions on phase separation and crystallization, time-temperature-transformation (TTT) diagrams for the system (65 - x)SiO2·25B2O3·(10 - y)Na2O·yCaO·xZrO2, which is used for fabricating alkali-durable porous glasses, were determined. The microstructures and properties, such as resistance to alkaline attack as a function of ZrO2 content, of the porous glasses fabricated on the basis of the developed TTT diagrams were examined. CaO and ZrO2 additions were shown to affect the locations of the noses in the TTT curves for phase separation and crystallization. The substituting of CaO for Na2O was effective for retaining ZrO2 in the skeleton of the porous glasses. The alkali resistance of ZrO2-containing porous glasses was 8-10 times superior to that of the porous glass without ZrO2. The results demonstrate that TTT diagrams can be used as guides for heat-treatment scheduling in processing or predicting of glass-forming ability and the onset of phase separation and crystallization in glass-forming systems.
|Number of pages||10|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - May 1997|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry